[Insight-users] ITK Dashboard: Our plan for fixing the problem with NonUniformBSpline

[Luis Ibanez]

The compilation problem that the (previously untested)
NonUniformBSpline class is displaying in many platforms:

http://public.kitware.com/dashboard.php?name=itk


arises from the expression in line 313:

The following code:

  vnl_matrix<double> B =
    vnl_matrix_inverse<double>( N_matrix.transpose() * N_matrix) *
N_matrix.transpose() * data_matrix;


is trying to solve the linear system

             X  = N * B

by doing:

        B = ( N' * N )^-1  *  N'  * X

This could be better done by using of
of the linear solvers in VXL. For example
the LSQR one that was fixed recently.


So, the suggested plan to solve this
compilation problem is to replace that
line 313 with a call to the vnl linear
system class and then to the vnl_lsqr
solver.

This should be happening later today...


    Luis
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